Current concepts on bronchoalveolar lavage cells in extrinsic allergic alveolitis.

Studies performed on cells recovered from bronchoalveolar lavage fluid and lung tissue sections have demonstrated that the alveolitis in patients with extrinsic allergic alveolitis is characterized by cells bearing suppressor/cytotoxic phenotype (T3+, T8+, HNK1+). Functional in vitro analyses demonstrated that lung T cells from these patients are able to provide suppressor function in a pokeweed-mitogen-induced B cell differentiation assay and nonspecific cytotoxic activity. This latter property has not been observed in subjects with asymptomatic extrinsic allergic alveolitis. The expansion of cells with suppressor and cytotoxic characteristics in the lung of these patients is likely to be related to a local immunologic response to the antigenic stimulus.